package cn.tedu.sp06z.hystrix;

import cn.tedu.sp01.web.util.JsonResult;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.stereotype.Component;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;

/**
 * 降级代码
 */
@Slf4j
@Component
public class ItemHystrix implements FallbackProvider {
    @Override
    /**
     * 设置需要进行降级的后台服务
     * "*":表示对所有服务都应用当前降级
     */
    public String getRoute() {
        return "item-service";
    }

    @Override
    /**
     * 向客户端发回降级的响应
     * - 错误提示
     * - 返回业务逻辑定义的任意数据
     */
    public ClientHttpResponse fallbackResponse(String route, Throwable cause) {
        return new ClientHttpResponse() {
            @Override
            public HttpStatus getStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR;
            }

            @Override
            public int getRawStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.value();
            }

            @Override
            public String getStatusText() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.getReasonPhrase();
            }

            @Override
            public void close() {
                //用来关闭输入流的
                //BAIS虚拟机中读取byte[]数组的流对象，不占用底层系统资源，不需要关闭
            }

            @Override
            public InputStream getBody() throws IOException {
                String json = JsonResult.err()
                        .code(500)
                        .msg("后台服务错误，请稍后重试")
                        .toString();
                //用BAIS封装json结果
                return new ByteArrayInputStream(json.getBytes("UTF-8"));
            }

            @Override
            public HttpHeaders getHeaders() {
                HttpHeaders httpHeaders = new HttpHeaders();
                httpHeaders.add("Content-Type", "application/json;charset=UTF-8");
                return httpHeaders;
            }
        };
    }
}
